首页 | 本学科首页   官方微博 | 高级检索  
文章检索
  按 检索   检索词:      
出版年份:   被引次数:   他引次数: 提示:输入*表示无穷大
  收费全文   69篇
  免费   4篇
林业   3篇
农学   1篇
  6篇
综合类   2篇
农作物   3篇
水产渔业   3篇
畜牧兽医   41篇
园艺   4篇
植物保护   10篇
  2022年   1篇
  2020年   6篇
  2019年   1篇
  2017年   2篇
  2016年   2篇
  2015年   1篇
  2014年   1篇
  2013年   1篇
  2012年   3篇
  2011年   4篇
  2010年   1篇
  2009年   1篇
  2008年   6篇
  2007年   9篇
  2006年   6篇
  2005年   5篇
  2004年   2篇
  2003年   3篇
  2002年   9篇
  2001年   2篇
  2000年   1篇
  1998年   2篇
  1997年   1篇
  1992年   1篇
  1985年   1篇
  1981年   1篇
排序方式: 共有73条查询结果,搜索用时 296 毫秒
1.
Objective: To evaluate the ability of capnography to document proper placement of nasoesophageal (NE) and nasogastric (NG) feeding tubes. This study was conducted in 3 phases. Phase I of this study was designed in order to test the efficacy of capnography to distinguish placement of a feeding tube in the alimentary tract versus the respiratory tract. Phase II was designed in order to document that carbon dioxide (CO2) could be measured through a polyvinyl chloride (PVC) feeding tube. Phase III was performed in order to evaluate the technique of continuous monitoring during insertion of the feeding tube into the esophagus and stomach as would be performed during a clinical‐tube placement. Design: Prospective study. Setting: Research laboratory. Animals: 24 adult dogs. Interventions: In Phase I, sedated dogs were instrumented with an intratracheal catheter and an 8 French feeding tube placed nasally into the distal esophagus and later advanced into the stomach. In Phase II, dogs were anesthetized and an 8 French feeding tube was placed down the endotracheal tube, then into the esophagus and later advanced into the stomach. In Phase III, sedated dogs were instrumented with an 8 French feeding tube inserted intranasally and then advanced to the level of the nasopharynx, distal esophagus and, lastly, the stomach. Fluoroscopy was used in order to determine location of the feeding tube. Measurements and main results: Phase I measurements included respiratory rate and CO2 from the trachea, esophagus, and stomach and pH of gastric fluid sample. Phase II measurements included respiratory rate and CO2 from the endotracheal tube, feeding tube in the endotracheal tube, feeding tube in the distal esophagus, and feeding tube in the stomach. Phase III data collection included respiratory rate and CO2 as the tube was passed through the nasal cavity, nasopharynx, esophagus and stomach. Phase I fluid samples were collected from 5 of the 9 dogs and had pH values from 1.68 to 4.20. In both phases, values for the respiratory rate and CO2 from the esophagus and stomach were 0 ± 0, significantly lower (P < 0.001) than the values from the trachea. In Phase II, there was no significant difference between the respiratory rates (P = 0.886) and CO2 (P = 0.705) readings obtained from the endotracheal tube compared to readings from the feeding tube in the endotracheal tube. In Phase III, there was a significant difference (P < 0.001) between the respiratory rates and CO2 readings obtained from the nasal cavity and the nasopharynx when compared to those readings obtained from the esophagus and stomach. Measurement of CO2 and respiratory rate resulted in a reading of 0 every time the feeding tube was in the esophagus or stomach. Conclusions: Capnography may be used in order to detect airway placement of NE and NG tubes.  相似文献   
2.
OBJECTIVE: To assess the reliability and accuracy of a predictive rectal thermometer, an infrared auricular thermometer designed for veterinary use, and a subcutaneous temperature-sensing microchip for measurement of core body temperature over various temperature conditions in dogs. DESIGN: Prospective study. ANIMALS: 8 purpose-bred dogs. PROCEDURES: A minimum of 7 days prior to study commencement, a subcutaneous temperature-sensing microchip was implanted in 1 of 3 locations (interscapular, lateral aspect of shoulder, or sacral region) in each dog. For comparison with temperatures measured via rectal thermometer, infrared auricular thermometer, and microchip, core body temperature was measured via a thermistor-tipped pulmonary artery (TTPA) catheter. Hypothermia was induced during anesthesia at the time of TTPA catheter placement; on 3 occasions after placement of the catheter, hyperthermia was induced via administration of a low dose of endotoxin. Near-simultaneous duplicate temperature measurements were recorded from the TTPA catheter, the rectal thermometer, auricular thermometer, and subcutaneous microchips during hypothermia, euthermia, and hyperthermia. Reliability (variability) of temperature measurement for each device and agreement between each device measurement and core body temperature were assessed. RESULTS: Variability between duplicate near-simultaneous temperature measurements was greatest for the auricular thermometer and least for the TTPA catheter. Measurements obtained by use of the rectal thermometer were in closest agreement with core body temperature; for all other devices, temperature readings typically underestimated core body temperature. CONCLUSIONS AND CLINICAL RELEVANCE: Among the 3 methods of temperature measurement, rectal thermometry provided the most accurate estimation of core body temperature in dogs.  相似文献   
3.
Single-fiber electromyography (SFEMG), a technique used to investigate neuromuscular transmission, has been described previously in the pelvic limb of dogs. Because preferential involvement of isolated muscle groups can occur in disorders of neuromuscular transmission, SFEMG was done in the peroneus longus (PL), extensor carpi radialis (ECR), and orbicularis oculi (OO) muscles of 10 adult, clinically normal dogs. Jitter was calculated as the mean absolute value of the consecutive differences in latency of 50 single muscle fiber action potentials after stimulation of intramuscular nerve bundles at the level of the motor point in at least 20 muscle fibers per muscle. Bilateral recordings were performed in 3 dogs. Mean jitter values were determined for each muscle, and differences among muscle groups and among dogs were compared. The upper limits of mean consecutive difference (mean plus 3 standard deviations) for the PL, ECR, and OO muscles were 21.94, 22.53, and 23.39 micros, respectively, and the upper limit of mean consecutive difference for individual muscle fibers in the respective fiber pools was 28.62, 36.39, and 35.68 micros. Jitter values for the ECR and OO were significantly higher than the jitter value for the PL muscle (P < .05). Significant differences among muscles or dogs or between sides were not observed for the ECR. Significant differences among dogs were observed for OO jitter values and were attributed to extremely low jitter values in 1 dog. Significant differences were demonstrated between sides for the PL and were attributed to small sample size. Results of this study provide normative data that can be used in the application of the stimulated SFEMG technique to dogs with suspected disorders of neuromuscular transmission.  相似文献   
4.
5.
Artificial reefs may provide a useful tool to enhance production of marine ornamentals and to divert detrimental harvesting activities from sensitive natural habitat. The efficacy of this strategy depends, in part, on the extent to which artificial reefs contribute to new production (vs. attract fishes from natural habitat) and therefore benefit harvested populations on a local and regional basis. Here the attraction and production hypotheses and their application to marine ornamentals are presented. Specifically, it is discussed how the strength and timing of density dependence can affect the response of fish population dynamics to artificial reefs. In addition to this discussion, examples of density dependence in marine ornamentals and related reef fishes are provided. Based on this information, a simple conceptual model is presented to clarify the role of density dependence, and this is followed by a discussion on the use of artificial reefs in the management and production of marine ornamentals. Finally, unresolved scientific issues that remain to be addressed are provided.  相似文献   
6.
Serine proteinase inhibitors (serpins) represent an important superfamily of endogenous inhibitors that regulate proteolytic events active in a variety of physiological functions. Immunological screening of a Schistosoma japonicum adult worm cDNA expression library with sera of Microtus fortis, a naturally resistant vertebrate host, has identified one clone that encoded for a sequence homologous to those of the serpin superfamily. The full-length sequence encoding S. japonicum serpin (Sj serpin) was amplified from adult worm cDNA by using 5'-RACE-PCR and subsequently cloned into the prokaryotic expression vector pET28c. The full-length Sj serpin fusion-protein with his-tag was expressed in E. coli, purified by affinity chromatography and used to immunize New Zealand white rabbits. Sj serpin is located on the tegument in S. japonicum adult worms. C57BL/6 mice immunized with Sj serpin induced the production of high levels of specific IgE and IgG1 subclass antibodies as well as a marked IL-4 response. Lymphocyte surface marker analysis revealed proliferation of CD19 expressing B cells, indicating a predominant Th2-type response to Sj serpin. Immunized mice developed moderate protection against infection of S. japonicum as demonstrated by a 36 and 39% reduction in the recovery of adult worms and eggs, respectively. These data suggested a role for Sj serpin as a vaccine candidate or as a novel target for anti-schistosome drugs.  相似文献   
7.
Morin C  Breuil C  Bernier L 《Phytopathology》2004,94(12):1323-1330
ABSTRACT Genomic DNA was extracted from 129 isolates of Ceratocystis resinifera, a species belonging to the C. coerulescens complex, and 19 polymorphic random amplified polymorphic DNA markers were used to study the population genetic structure of this fungus. The analysis suggested a moderate value for genetic diversity (H(S) = 0.209). However, when monomorphic markers and rare alleles, representing 89 markers, also were included in the calculation, the genetic diversity of Canadian populations of C. resinifera appeared to be much lower (H(S) = 0.045). This could be explained by two hypotheses: (i) recent introduction of this species into North America and (ii) clonal reproduction (by selfing). No specialization by C. resinifera for coniferous tree species was observed based on genetic differentiation index between isolates sampled from Pinus and Picea spp. and on phylogenetic analysis using Dice coefficient of association. In spite of a low genetic diversity, a very high genetic differentiation was observed among the nine geographical populations studied (F(ST) = 20.8%). The genetic differences were especially striking when populations from Eastern Canada were compared with populations from Western Canada (phiST = 0.27%; P < 0.001), suggesting that a geographic reproductive barrier occurs in Central Canada. This barrier may be the consequence of a weak migration of insect vectors of C. resinifera due to reduced presence of hosts in the Canadian Great Plains, where extensive agriculture occurs. However, results from pairwise F(ST) matrix and phylogeny of haplotypes suggest that the barrier is not totally impenetrable because some gene flow occurred from the west and from the east in the Big River (Saskatchewan) population located in the middle of the Great Plains.  相似文献   
8.
Surgical techniques for castration of the Vietnamese pot-bellied boar and outcome are described. Vietnamese pot-bellied pig (VPBP) boars (n = 8) were admitted for castration. Data retrieved from medical records (2002–2011) for these pigs included signalment, history, reason for castration, perioperative management, surgical technique, and complications. Follow-up information was obtained from owners. A scrotal approach with closed technique was used for 6 boars with normally descended testes. A scrotal approach and open technique was used in 1 inguinal cryptorchid boar. In a hemicastrated abdominal cryptorchid boar an ipsilateral parainguinal approach was used. No complications occurred. Castration of the Vietnamese pot-bellied boar is associated with minimal complications and a satisfactory cosmetic outcome. We recommend the routine closure of the external inguinal rings, a simple and fast procedure that may prevent post-castration inguinal herniation.  相似文献   
9.
ABSTRACT: BACKGROUND: Phloem-feeding insects are among the most devastating pests worldwide. They not only cause damage by feeding from the phloem, thereby depleting the plant from photo-assimilates, but also by vectoring viruses. Until now, the main way to prevent such problems is the frequent use of insecticides. Applying resistant varieties would be a more environmental friendly and sustainable solution. For this, resistant sources need to be identified first. Up to now there were no methods suitable for high throughput phenotyping of plant germplasm to identify sources of resistance towards phloem-feeding insects. RESULTS: In this paper we present a high throughput screening system to identify plants with an increased resistance against aphids. Its versatility is demonstrated using an Arabidopsis thaliana activation tag mutant line collection. This system consists of the green peach aphid Myzus persicae (Sulzer) and the circulative virus Turnip yellows virus (TuYV). In an initial screening, with one plant representing one mutant line, 13 virus-free mutant lines were identified by ELISA. Using seeds produced from these lines, the putative candidates were re-evaluated and characterized, resulting in nine lines with increased resistance towards the aphid. CONCLUSIONS: This M. persicae-TuYV screening system is an efficient, reliable and quick procedure to identify among thousands of mutated lines those resistant to aphids. In our study, nine mutant lines with increased resistance against the aphid were selected among 5160 mutant lines in just 5 months by one person. The system can be extended to other phloem-feeding insects and circulative viruses to identify insect resistant sources from several collections, including for example genebanks and artificially prepared mutant collections.  相似文献   
10.
Fifteen dogs with extrahepatic biliary tract disease underwent cholecystoenterostomy. Long-term survivors were significantly older at presentation (mean age 140.5 months) than dogs that survived the first 20 days after surgery but subsequently died from causes related to the surgery or hepatobiliary disease (mean age 72 months). Dogs that died during the first 20 days had significantly more complications in the hospital than dogs that survived this period. The type of underlying hepatobiliary disease (i.e., benign or malignant) was not associated with either short-term outcome or long-term survival. Eight dogs died from causes related to surgery or hepatobiliary disease. Long-term complications included hepatic abscesses, acquired portosystemic shunts, pancreatitis, and vomiting.  相似文献   
设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号